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Microwave-assisted biosynthesis of silver nanoparticles for potential antibacterial activity

applied Nanoscience (Switzerland) 2024年第12期14卷 1115-1124页

作者： Kala, Anuskha Uniyal, Santoshi Saini, Krati Dhyani, Reena Joshi, Deepika Verma, Rashmi Kar, Kamal K. Chamoli, Pankaj School of Basic and Applied Sciences Department of Biotechnology Shri Guru Ram Rai University Uttarakhand Dehradun248001 India School of Basic and Applied Sciences Department of Physics Shri Guru Ram Rai University Uttarakhand Dehradun248001 India Department of Physics Women Institue of Technology Uttarakhand Dehradun248007 India Siddhartha Institute of Pharmacy Uttarakhand Dehradun248013 India Advanced Nanoengineering Materials Laboratory Department of Mechanical Engineering and Materials Science Programme Indian Institute of Technology Kanpur Kanpur208016 India

The present study demonstrates the creation of silver nanoparticles (Ag NPs) in an environmentally benign manner from Cymbopogon citratus leaves extracts by employing microwave-assisted synthesis at a low power of 400 W for a short period of 180 s. The produced Ag NPs are thoroughly characterized using methods like X-ray diffraction (XRD), UV–visible spectroscopy, scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS). These Ag NPs form clusters and have unique plate-like shapes with average particle size of ~ 165 nm. To evaluate their antibacterial activity, the produced Ag NPs are tested against both gram-positive bacteria (S. aureus) and gram-negative bacteria (E. Coli, S. typhi, and Pseudomonas) at varied concentrations (1–5 mg/L). The results show strong antibacterial activity, against both gram-positive bacteria (S. aureus) and gram-negative bacteria (E. Coli, S. typhi, and Pseudomonas);and show the largest zone of inhibition diameters at 23 mm (~ 3 mg/L) and 26 mm (~ 5 mg/L) for S. aureus and Pseudomonas, respectively. The ecological potential of Cymbopogon citratus extracts as sources for the environmentally friendly synthesis of Ag NPs is highlighted in this work and the produced Ag NPs are a viable option for antibacterial treatments against pathogenic microbes. © King Abdulaziz City for Science and Technology 2024.

关键词： Silver nanoparticles

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Cavity-enhanced photoacoustic dual-comb spectroscopy

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Light(Science & Applications) 2024年第4期13卷 610-618页

作者： Zhen Wang Qinxue Nie Haojia Sun Qiang Wang Simone Borri Paolo De Natale Wei Ren Department of Mechanical and Automation Engineering The Chinese University of Hong KongNew TerritoriesHong Kong SARChina. State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences130033 ChangchunChina. CNRINO-Istituto Nazionale di Ottica and LENS-European Laboratory for Nonlinear Spectroscopy50019 Sesto FiorentinoItaly

Photoacoustic dual-comb spectroscopy(DCS),converting spectral information in the optical frequency domain to the audio frequency domain via multi-heterodyne beating,enables background-free spectral measurements with high resolution and broad ***,the detection sensitivity remains limited due to the low power of individual comb lines and the lack of broadband acoustic ***,we develop cavity-enhanced photoacoustic DCS,which overcomes these limitations by using a high-finesse optical cavity for the power amplification of dual-frequency combs and a broadband acoustic resonator with a flat-top frequency *** demonstrate high-resolution spectroscopic measurements of trace amounts of C2H2,NH3 and CO in the entire telecommunications *** method shows a minimum detection limit of 0.6 ppb C2H2 at the measurement time of 100 s,corresponding to the noise equivalent absorption coefficient of 7×10−10 cm−*** proposed cavityenhanced photoacoustic DCS may open new avenues for ultrasensitive,high-resolution,and multi-species gas detection with widespread applications.

关键词： individual cavity spectroscopy

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Exact Instability Margin Analysis and Minimum-Norm Strong Stabilization - Phase Change Rate Maximization

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IEEE Transactions on Automatic Control 2024年第4期69卷 2084-2099页

作者： Hara, Shinji Kao, Chung-Yao Khong, Sei Zhen Iwasaki, Tetsuya Hori, Yutaka Tokyo Institute of Technology Global Scientific Information and Computing Center Tokyo152-8550 Japan National Sun Yat-Sen University Department of Electrical Engineering Kaohsiung80421 Taiwan University of California at Los Angeles Department of Mechanical and Aerospace Engineering Los AngelesCA90095 United States Keio University Applied Physics and Physico Informatics Yokohama223-8522 Japan Monaco

This article is concerned with a new optimization problem named 'phase change rate maximization' for single-input-single-output linear time-invariant systems. The problem relates to two control problems, namely robust instability analysis against stable perturbations and minimum-norm strong stabilization. We define an index of the instability margin called 'robust instability radius (RIR)' as the smallest H∞-norm of a stable perturbation that stabilizes a given unstable system. This article has two main contributions. It is first shown that the problem of finding the exact RIR via the small-gain condition can be transformed into the problem of maximizing the phase change rate at the peak frequency with a phase constraint. Then, we show that the maximum is attained by a constant or a first-order all-pass function and derive conditions, under which the RIR can be exactly characterized, in terms of the phase change rate. Two practical applications are provided to illustrate the utility of our results. © 1963-2012 IEEE.

关键词： Robust control

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Eco-friendly synthesis, characterization, and antimicrobial studies of Zinc oxide nanoparticles using Cassia Javanica Leaf extract

Eco-friendly synthesis, characterization, and antimicrobial ...

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2024 International Conference on Science, engineering and Business for Driving Sustainable Development Goals, SEB4SDG 2024

作者： Owoeye, Taiwo Felicia Bamisaye, Abayomi Eterigho, Emetere Moses Afolalu, Sunday A. Monye, Stella Isioma Oluwatoyin, Ojo Augustine Lead City University Department of Chemical Sciences Ibadan Nigeria Covenant University Department of Chemistry Sango Ota Nigeria Lead City University Faculty of Natural and Applied Sciences Department of Chemical Sciences Ibadan Nigeria BOWEN University Faculty of Engineering Department of Physics Iwo Nigeria Afe Babalola University Department of Mechanical and Mechatronics Engineering Ado-Ekiti Nigeria Science University of Johannesburg Department of Mechanical Engineering South Africa Afe Babalola University Department of Mechanical and Mechatronics Department Ado-Ekiti Nigeria Afe Babalola University Mechanical and Mechatronics Ado-Ekiti Nigeria

ISBN: (纸本)9798350358155

The green approach for metal oxide Nanoparticles (NPs) synthesis is a current discuss in material science and nanotechnology, which is quick, simple, cost-effective, and environmentally friendly. This study aims at the biogenic zinc oxide nanoparticles synthesis (ZnONPs) using Cassia Javanica leaf extracts and Analyzing its antibacterial properties activities;Zones of Inhibition (ZI) and Minimum Inhibitory Concentration (MIC) on Salmonella, Candida, Escherichia coli, Staphylococcus, and Pseudomonas aeruginosa. The ZnONPs were characterized using a UV-Vis spectrophotometer, XRD, FTIR, EDX, and SEM. The FTIR shows that the metal oxide nanoparticle wavenumber was at 700cm-1, which was corroborated by EDX chemical *** show spherical crystalline nanoparticles having an average size of particles of 41.85 nm. The recorded ZI values for Salmonella, Candida, Escherichia coli, Staphylococcus, and Pseudomonas aeruginosa are 32.00, 48.00, 0.00, 34.00 and 40.00 mm respectively. Also, the MIC for Salmonella, Candida, Escherichia coli, Staphylococcus, and Pseudomonas aeruginosa are 7.81, 3.90, 0.00, 31.25 and 7.81 mg/mL respectively. The findings of this study revealed the antimicrobial properties of Zinc oxide nanoparticles (ZnONPs) using Cassia Javanica leaf extract suggesting that it is a possible contender for use in biomedical applications. © 2024 IEEE.

关键词： Yeast

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Laboratory study of wind impact on steep unidirectional waves in a long tank

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Physical Review Fluids 2024年第10期9卷 104801页

作者： Zitan Zhang Tianning Tang Xiaobo Zheng Wentao Xu Lijun Zhang Jung-hoon Lee Thomas A. A. Adcock Jason P. Monty Alexey Slunyaev Ton S. van den Bremer Ye Li Multifunction Towing Tank Laboratory Department of Engineering Science College of Energy and Power Engineering Lanzhou University of Technology Lanzhou 730050 China Department of Mechanical Engineering The Institute of Applied Physics Faculty of Civil Engineering and Geosciences Department of Ocean Science and Engineering School of Engineering The Department of Civil and Mechanical Engineering Department of Wind and Energy Systems

Understanding the effect of wind forcing on steep unidirectional waves is important for the study of wind-wave interaction. In this paper, unidirectional random wave experiments are carried out in a large-scale wave tank in which waves interacted with turbulent wind generated by wind fans. The properties and evolution of deep-water gravity waves subject to following wind forcing are investigated through parametric laboratory experiments. The effect of wind forcing on the significant wave height varies with the initial wave steepness. Wind forcing increases the growth of waves of small initial steepness but attenuates large, steep waves as a result of the vertical angle of the wind to the free surface in our experiments. The energy input by wind forcing increases the high-frequency tail of the wave spectra, and this effect increases with fetch. The mean frequency increases under wind forcing. The effect of wind forcing on the probability of extreme events is investigated. Wind forcing enhances wave steepness, resulting in a deviation of the exceedance probability from first-order and second-order theoretical distributions and an increased value of kurtosis but not skewness.

关键词： Hydrodynamic waves Surface gravity waves

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Interacting Phonons between Layers in Raman Spectra of Carbon Nanotubes inside Boron Nitride Nanotubes

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Journal of Physical Chemistry Letters 2023年第45期14卷 10263-10270页

作者： Gulo, Desman Perdamaian Hung, Nguyen Tuan Chen, Wei-Liang Wang, Shuhui Liu, Ming Kauppinen, Esko I. Maruyama, Shigeo Chang, Yu-Ming Saito, Riichiro Liu, Hsiang-Lin Department of Physics National Taiwan Normal University Taipei11677 Taiwan Department of Physics Tohoku University Sendai980-8578 Japan Frontier Research Institute for Interdisciplinary Sciences Tohoku University Sendai980-8578 Japan Center for Condensed Matter Sciences National Taiwan University Taipei10617 Taiwan Department of Mechanical Engineering School of Engineering The University of Tokyo Tokyo113-8656 Japan Department of Applied Physics Aalto University School of Science Espoo 15100 AaltoFI-00076 Finland

We present the resonant Raman spectra of a single-wall carbon nanotube inside a multiwall boron nitride nanotube (SWNT@BNNT). At EL = 1.58 eV, SWNT@BNNT exhibited resonant Raman spectra at 807 (ωBN) and 804 cm-1 (ωGr). Their intensities almost disappeared at EL = 2.33 eV. We assigned ωBN to the out-of-plane BN phonon mode that coupled with ωGr. At EL = 4.66 eV, the G+ and G- bands of the SWNT@BNNT red-shifted 3.8 cm-1 compared with the SWNT, suggesting the interwall interactions between the in-plane modes of SWNT and BNNT. Moreover, the E2g mode of the BNNT in SWNT@BNNT appeared at 1370.3 ± 0.1 cm-1, which is undistinguishable for EL © 2023 American Chemical Society.

关键词： Raman scattering

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Developing a Floating Robot for mechanical Control of Water Hyacinth 3

Developing a Floating Robot for Mechanical Control of Water ...

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3rd International Mobile, Intelligent, and Ubiquitous Computing Conference, MIUCC 2023

作者： Elsayed, Mostafa E.A. Mohamed, Ahmed K.A. Shaaban, Mahmoud Abdelrahman, Mohamed A. Ahmed, Mohamed E. A. E. Rashed, Mostafa R. Benha University Automation and Energy Technology Lab. Shoubra Faculty of Engineering Mechanical Engineering Department Cairo Egypt Benha University Agricultural Power and Machinery Faculty of Agriculture Department of Agricultural Engineering Kalubia Egypt School of Engineering and Applied Sciences Nile University Smart Engineering Systems Center Mechanical Engineering Program Giza Egypt Benha University Combustion and Energy Technology Lab. Shoubra Faculty of Engineering Mechanical Engineering Department Cairo Egypt Benha University Shoubra Faculty of Engineering Mechanical Engineering Department Cairo Egypt University for Technology and Information Faculty of Engineering Modern Mechanical Engineering Department Cairo Egypt

ISBN: (纸本)9798350306231

Water hyacinth has become widespread in freshwater bodies in several countries, leading to various issues, particularly its substantial water consumption and the resulting need to control its growth. Among the different methods of controlling water hyacinth, mechanical control stands out as the most effective and environmentally friendly approach. A proposed harvester robot has been developed, capable of efficiently cutting and collecting water hyacinth from the water's surface. The robot boasts several advantages, including its ability to operate in narrow water paths and lakes, use clean energy sources to preserve the water ecology, employ a GPS module for safety and error detection, and generate maps for evaluating work and predicting annual growth. When compared to other technologies dealing with water hyacinth, this innovative water hyacinth harvesting robot presents a significantly lower cost of 0.01 /kg, making it an optimal solution for addressing water hyacinth problems. © 2023 IEEE.

关键词： Weed control

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Investigation of optical structural and physical properties of ternary bismuth tellurite glasses

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Materials Today: Proceedings 2022年 56卷 1313-1316页

作者： Kumbhakar, R.P. Dhiman, S.K. Mahajan, S.K. Ansari, Ghizal F. Physics Department Madhyanchal Professional University Bhopal46204 India Department of Mechanical Engineering Birla Institute of Technology Mesra Ranchi835215 India Departments of Applied Physics Samrat Ashok Technological Institute MP Vidisha464001 India

Synthesis of heavy metal oxide doped ternary glasses named bismuth tellurite (BT) glasses with batch composition (90-x)%TeO2 –x%Bi2O3- 10 %Na2CO3 (x = 8,12,16,20 mol%) have been done by conventional melting and quenching method. Structures of prepared sample were checked by X-Ray Diffraction. Thermal study is done by Differential Scanning Calorimetry (DSC) to get the information of glass transition and melting temperatures. Heaviness of sample glasses is justified by measuring density (ρ). Other physical properties such as Oxygen packing density (OPD), Bi3+ ion concentration (N), polaron radius Rp and inter-nuclear distance Ri also evaluated which manifest the impact of Bi2O3 on glass structure. The numerous photonic properties like transmittance, absorbance, cutoff wavelength, optical energy band gap in direct and indirect allowed transition, refractive index (n) and Urbach energy were evaluated. © 2022

关键词： Bismuth compounds

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Coordination of oscillators driven by non-identical van der Pol excitation interacting via Huygens’ coupling

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IFAC-PapersOnLine 2024年第5期58卷 34-39页

作者： J.A. Villalobos Torres J. Pena Ramirez H. Nijmeijer Applied Physics Division CICESE Ensenada Baja California México Department of Mechanical Engineering Eindhoven University of Technology The Netherlands

It is well-known that coupled oscillators may exhibit different types of collective behavior, like for example full synchronization, coordinated motion, cooperative behavior, among others. This is indeed the topic addressed in this paper. In particular, we briefly report on a special coordinated motion observed in a triplet of mechanical oscillators with Huygens’ coupling: two oscillators achieve complete synchronization between them but they oscillate in anti-phase and with different amplitude with respect to the third oscillator. Each oscillator is equipped with a van der Pol term, in order to have self-sustained oscillations and furthermore, it is assumed that all the parameters of the oscillators are identical except for the parameter of the van der Pol term, which is different for one of the oscillators, ultimately resulting in oscillations with different amplitudes. Then, by using a transformation, the model of the system is reduced and the resulting model is analyzed using the Poincaré method of perturbation. It is analytically demonstrated that the coordinated motion above described exists and is asymptotically stable provided that the parameter discrepancy between the oscillators satisfies an specific condition. These results are further illustrated by numerical simulations and are experimentally validated.

关键词： Synchronization Huygens’ coupling mechanical oscillator Poincaré method

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mechanical properties and thermal stability of AA5052 processed by high-pressure torsion

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Materials Today: Proceedings 2022年 66卷 2685-2688页

作者： Aziz, A.M. Mohamed, I.F. Omar, M.Z. Sajuri, Z. Othman, N.K. Department of Mechanical and Manufacturing Engineering Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia Selangor Bangi 43600 Malaysia Department of Applied Physics Faculty of Science and Technology Universiti Kebangsaan Malaysia Selangor Bangi 43600 Malaysia

High-pressure torsion (HPT) is a technique for increasing material strength through grain refining and dislocation strengthening. The goal of this research is to investigate at the material's stability after HPT processing and high-temperature exposure. Prior to HPT processing, the 10 mm diameter AA5052 sample was solution treated at 550 °C for 5 h. The sample was then processed by HPT at 6 GPa and torsional force of 1.0 rpm for 5 turns at room temperature. Following that, the sample was annealed for 1 h at 200 °C. When compared to the solution-treated state, the Vickers microhardness and tensile strength after 5 turns reveal a 135% and 199% improvement in hardness and strength, respectively. Due to the annihilation mechanism, the hardness and tensile strength of the material reduced by up to 25% and 27% respectively after exposure at 200 °C. The result shows a tremendous improvement in the mechanical properties after HPT processing as well as adequate stability at 200 °C. The TEM analysis revealed that HPT processing resulted in grain size refinement and high-angle grain boundaries which contribute to the excellent mechanical properties. © 2022

关键词： Tensile strength

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